Arborist Rigging Blocks

Buying guide

Choosing an arborist block

Match the block to your rope diameter and to the loads you expect. A steel block is heavy but tough enough for big removals; smaller aluminum blocks suit lighter rigging. The sling attaching the block should be rated at least as high as the block.

Remember that the load on the block can be nearly double the load on the rope when the line runs back down, and more under shock loading. Keep drops short and inspect the sheave and side plates often.

Setting a block

Hang the block on a rated sling wrapped around solid wood above the piece being cut, and keep it close to the trunk to reduce leverage on the stem. Make sure the rope runs cleanly through the sheave without rubbing the side plates or sling.

Arborist block and tackle setups add mechanical advantage for lifting or tensioning, but they also multiply force on the anchor. Check sheave bearings or bushings for smooth spin, side plates for bends, and the attachment point for wear. Retire any block that has been overloaded or dropped from height onto hard ground.